Hydroponics, the science of feeding a balanced nutrient solution of macro and micro nutrients to plants to promote rapid growth and high yields, has proved to be successful in both laboratory and field use. There are two methods for supplying the enriched nutrient solution to plants that dominate the current hydroponic market:
Method "A" utilizes a holding pit for the enriched liquid, and pumps the liquid to the far end of a growing tray, and the liquid returns to the holding pit by gravity flow through an inert medium in which the plants have been rooted.
Method "B" mixes the nutrient with water, pumping the enriched liquid through tubes in which small holes have been provided to release the liquid in the vicinity of the plants.
Both methods of supplying the enriched liquid to the plants have inherent disadvantages:
Method "A" takes up excessive valuable greenhouse space for the liquid holding pit; the nutrient in the liquid solution tends to settle in the pit between use; the flooded trays tend to leach out the heavier nutrients first, resulting in an uneven distribution of enriched liquid to the plants; and, the plants must be uprooted from the planting medium to be moved.
Method "B" provides no means of retrieval of the excess enriched liquid; the liquid is top-fed, which increases the hazards of overwatering; the small holes in the supply tubes easily clog, providing uneven distribution of the liquid; and, the tap water is often far cooler than room temperature, tending to shock the delicate plant roots upon application, thus stressing the plants.